Update C# wrapper to support both desktop and UWP projects

Summary:
The C# wrapper project has been changed to a NETStandard (1.1) PCL allowing it
to be consumed by any project targeting .NET4.5 or greater including .NETCore
and UWP projects... The C# wrapper uses P/Invoke to call into the Native Yoga
DLL...

The "Yoga" C++ project has been updated to support ARM builds...

Added the ability to generate nuget packages for the C# wrapper that supports
copying the native DLLs to the target output directory.

Closes: https://github.com/facebook/yoga/pull/283

Reviewed By: splhack, emilsjolander

Differential Revision: D4381455

Pulled By: JoelMarcey

fbshipit-source-id: e6dc4190caa824ac63d5d5ee2eb4c7914efbb00f

csharp/Yoga/resource.h

@@ -0,0 +1,14 @@
+//{{NO_DEPENDENCIES}}
+// Microsoft Visual C++ generated include file.
+// Used by Yoga.rc
+
+// Next default values for new objects
+//
+#ifdef APSTUDIO_INVOKED
+#ifndef APSTUDIO_READONLY_SYMBOLS
+#define _APS_NEXT_RESOURCE_VALUE        101
+#define _APS_NEXT_COMMAND_VALUE         40001
+#define _APS_NEXT_CONTROL_VALUE         1001
+#define _APS_NEXT_SYMED_VALUE           101
+#endif
+#endif